Collection of indicators and development of an evaluation index for the practical assessment of animal welfare aspects, based on the example of German trout-farming

In this study, using the example of rainbow trout during the grow-out phase in German aquaculture, an evaluation index is developed which assesses individual animal protection aspects / animal welfare indicators and correlates them to one another. To ensure practical relevance and to keep the system simple and intuitive, a vivid "thumbs up, thumbs horizontal, thumbs down" system will be developed. The fish farmer is thus given the opportunity to check his methods and processes, and to quickly and concretely recognize animal welfare relevant weaknesses in his production. Improvement opportunities for animal welfare and its implementation in terms of sustainability and cost-effectiveness are part of the project.

Further it will be identified whether, and if so, how the "5 freedoms" described for farmed livestock, which today form the basis for various animal health measurement and evaluation systems on farm animals (pigs, cattle, chickens, etc.), can be adapted for fish.

By means of the evaluation index, it is possible to assess the prevailing methods and systems of trout-farming in terms of animal welfare, and the extent to which animal welfare components are being implemented. By using an evaluation sheet, the fish farmer can communicate his animal welfare efforts and actions directly to the consumer if needed. For the consumer, this provides the opportunity to make his purchasing decisions based on animal welfare through the product-specific animal welfare assessment of the food trout.

The indicators, indicator target values and weighting factors used for the evaluation index are discussed with a panel of experts and within the framework of specialist colloquia and DLG events. The evaluation index is applied and evaluated in a total of nine farms (three farms with extensive and intensive ponds and three farms with raceways). In addition, during the test phase of the evaluation index, a small sample of trout from different farms will be examined pathological-morphologically, pathological-histologically, microbiological and molecular biologically for signs of disease, the influence of stress and its possible influences on the immune system. It is examined whether the assessment of the individual protection aspects / animal welfare indicators are conforming with the results of the health examination and may thus complement the evaluation index.